Multidecker complexes

The di- and triborolyl ligands tend to i -coordination in sandwichforming reactions. There is a clear-cut tendency for stacking processes followed by the formation of multidecker species and often stabilization of the unusual oxidation states of the transition metals. The route to the linked sandwich and multidecker complexes is attractive for materials chemistry. Thia- and azaborolyl organome-tallic chemistry follows the same trends, although in the azaborolyl complexes the i -rather than i -coordination is sometimes realized. Moreover, coordination via the boron atom is known. In the B, N, Si-heterocycles, the heteroring is j " -coordinated. 

In complexes containing a planar E unit, it is common for the addition of metal fragments to give a multidecker complex [Eqs. (93)-(96)441,454,479,485]. A metal fragment may attach to several E atoms to give a more complicated cluster core as in Eqs. (97) and (98), 494 or may insert... 

Methods for regiospecific introduction of halogens at boron vertices in 7-vertex MC2B4 clusters, and for organosubstitution at boron in n/do-MCaBs compounds, have been developed in recent years and are summarized in Scheme 1. The approaches shown, combined with available routes to C-substituted derivatives, have been used to advantage in preparing B- and C-functionalized multidecker complexes and linked dimers. However, recent synthetic objectives in our program require more versatility in... 

The synthesis of a tricarbonyl cobalt 1,3-diborolyl complex has been reported. The same ligand features in symmetrical and unsymmetrical multidecker complexes of platinum with iron, cobalt and nickel and in the first reported hexadecker sandwich complex. Thia-dlborole complexes of nickel and cobalt have also... 

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